The present invention relates to a fly-cutter milling machine for the simultaneous milling of a plurality of grooves (12) in rotating workpieces (2) by means of a fly cutter (3) which protrudes radially outward on a rotating tool holder, the speed of revolution of the tool holder and the speed of revolution of the workpiece being in a ratio which is determined by the number of grooves of the workpiece.
Such a fly-cutter milling machine is known from Federal Republic of Germany Pat. No. 1 921 514. The tool-hold shaft and the workpiece turning shaft are at right angles and are skewed to each other. By use of a suitable transmission ratio, grooves to be provided on the workpiece and having the same circumferential spacing can be produced with high cutting speed. Coolant is not necessary for this, due to the free-cutting tool lip. The grooves produced in this manner are similar in their geometrical cross sectional shape to the cutting profile of a fly cutter but they are somewhat enlarged due to the free cutting. Since cross sectional shape of the grooves is dependent on the cutting profile of the fly cutter, the fly circle of the fly cutter, the diameter of the workpiece, the indexing and the depth of cut, it is necessary, upon a change in one of these parameters, to select a fly-cutter lip of different profile.
In order that, despite a change of a parameter of the tool lip which determines the profile of the groove, precisely adapted grooves can be produced on the workpiece by means of a single fly cutter. It is known from Federal Republic of Germany Pat. No. 26 50 955 to arrange the tool holder to be pivotable and lockable around a shaft, the shaft intersecting the axis of rotation of the workpiece and the tool-holder axis at right angles. The similarity in shape between groove profile and tool cutting lip requires complicated undercut fly cutters. The tool holder must also be fixed in its angular position in accordance with the groove profile desired.
The object of the present invention is to develop a fly-cutter milling machine of the type indicated in a manner which is simple to manufacture, in such a way that a groove profile which is precisely adapted to the tool cutting lip can be produced on the workpiece and that this can be done without any angular displacement of the tool holder with respect to the axis of rotation of the workpiece.